AI Product Index / Content Signals declared in robots.txt
It states how your content may be used — search, AI answers, training — in the one place a crawler already looks. Under 5% of sites declare it, so it is a differentiator rather than a baseline, and the common default was written for publishers protecting an archive rather than for anyone who wants to be read.
Add a Content-Signal line to robots.txt (contentsignals.org) stating how your content may be used: search, ai-input, ai-train. Roughly 4% of sites declare it, so it is a differentiator rather than a baseline — and pick the values deliberately, because the common default (ai-train=no) suits a publisher protecting an archive and not everyone is one.
Free, no signup, same endpoint that produced every grade on the leaderboard:
curl "https://index.percall.dev/api/score?url=https://your-site.example"It returns the letter grade and every check by name with pass/fail. The
$0.05 call at POST /api/audit adds why each one failed and a
snippet with your origin already in it.